Hundreds of people desperate to withdraw money lined up outside the branches of IndyMac Bancorp after the California bank was seized in July by the Federal Deposit Insurance Corp.

FDIC officials were stunned. The bank now belonged to the federal government. The deposits were insured by the FDIC. Bank runs were supposed to end once the government arrived.

"It had just been so long since there had been a significant bank failure in the U.S.," FDIC Chairman Sheila C. Bair said in an interview yesterday. "People had just forgotten that banks fail."

And, she added, they had forgotten about the FDIC.

Three months later, Bair and her agency have moved to the forefront of the government's response to the financial crisis. Observers say the FDIC's recent actions may offer the best hope for limiting the consequences of the crisis.

On Tuesday, Bair may have broken the deadlock over the administration's $700 billion bailout plan by proposing to increase the FDIC guarantee of bank deposits beyond the limit of $100,000 per account.

On Monday, Bair brokered the sale of Wachovia to Citigroup in a deal that experts said could serve as a model for limiting the cost and consequences of dealing with troubled banks.

And in August, Bair announced a program to modify thousands of the mortgage loans held by IndyMac to help homeowners avoid foreclosure. The program may be expanded to include other loans that the government buys as part of the bailout.

Bair, who resumed a long career in public service when she took over the FDIC in 2006, is characteristically pragmatic about the opportunity and the responsibility.

"I don't think we really have any choice, and we've been preparing for some time," she said. "We saw this coming before anyone else did, and we're as ready as we can be."

People who have worked with Bair describe her as well-suited to the challenge. They say she is principled and blunt without being confrontational. She has the talent, more often observed in diplomats than in banking regulators, for simultaneously communicating opposition to an idea and personal warmth for the holder of the idea. And she knows how to make a deal.

Martin Eakes, chief executive of the Center for Responsible Lending, which seeks stricter mortgage regulations, described a meeting organized by Bair in early 2007 and attended by consumer advocates and mortgage executives.